WO2019103196A1 - Method and apparatus for reporting beam in wireless communication system - Google Patents

Abstract

According to one embodiment of the present specification, a method by which a terminal can report beam information in a wireless communication system can be provided, and the method by which a terminal reports beam information comprises the steps of: acquiring beam reporting-related information from a base station; triggering beam reporting; receiving a beam reporting-related signal from the base station; measuring the beam reporting-related signal; and reporting the beam information to the base station on the basis of the measured signal, wherein the beam information includes information on the best beam among all available beams and the beam information can be reported on the basis of reporting settings.

Description

METHOD AND APPARATUS FOR REPORTING BEAM IN A WIRELESS COMMUNICATION SYSTEM

The present disclosure relates to wireless communication systems, and more particularly, to a method and apparatus for reporting beam information.

A very high frequency wireless communication system using a millimeter wave (mmWave) is configured to operate at a center frequency of several GHz to several tens GHz. Due to the characteristics of the center frequency, the path loss in the shadow area can be prominent in the mmWave communication system. Considering this path attenuation, beamforming of the signal transmitted to the terminal in the mmWave communication system needs to be elaborately designed. There is also a need for a method of reporting and operating on beam information.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of reporting beam information.

It is another object of the present invention to provide a method for transmitting best beam information among a plurality of beams.

It is another object of the present invention to provide a report setting method for reducing the amount of information to be transmitted.

According to one embodiment of the present disclosure, a method may be provided by a terminal in a wireless communication system to report beam information. A method for a terminal to report beam information includes the steps of the terminal obtaining beam reporting related information from the base station, triggering beam reporting, receiving a beam reporting related signal from the base station, measuring a beam reporting related signal, And reporting the beam information to the base station based on the received signal. At this time, the beam information includes information on the best beam among all available beams, and the beam information can be reported based on a reporting configuration.

According to one embodiment of the present disclosure, a terminal for reporting beam information in a wireless communication system can be provided. At this time, a receiver for receiving a signal, a transmitter for transmitting a signal, and a processor for controlling a receiver and a transmitter may be included. At this time, the processor acquires the beam reporting related information from the base station, triggers the beam reporting, receives the beam reporting related signal from the base station, measures the beam reporting related signal, and reports the beam information to the base station based on the measured signal , Where the beam information includes information about the best beam among all available beams, and the beam information can be reported based on the reporting settings.

In addition, the following matters can be commonly applied to a method and an apparatus for reporting beam information in a wireless communication system.

According to an embodiment of the present invention, the reporting configuration is composed of two bits, and the terminal reports the reporting setting together with the beam information to the base station, and the base station can recover the beam information based on the reporting setting.

According to an embodiment of the present invention, when the reporting setting is the first value, the beam information includes all the measured value information of the first beam of the best beam, and the measured information of the first beam of the best beam The information may include only the difference offset information based on the difference from the first beam.

Also, according to one embodiment of the present disclosure, when the reporting setting is a second value, the beam information includes all the measured value information for the first one of the best beams, and for the other beams except for the first one of the best beams The information may include only relative difference offset information based on the difference from the adjacent beam.

Also, according to one embodiment of the present disclosure, when the reporting setting is a third value, the available measurements of the total beams have a plurality of crest-based distributions, and the beam information may include only information about the beams corresponding to the crest have.

Here, according to one embodiment of the present disclosure, the measurements of the total available beams are distributed based on the beam index, and the beams corresponding to the crest have a measured value higher than the measured value of the beams corresponding to the adjacent beam index on both sides A branch can mean a beam.

Also, according to one embodiment of the present disclosure, when the reporting setting is a fourth value, the measurements of available full beams have a distribution based on one crest, and the beam information includes a beam having the largest measured value corresponding to the crest May be included.

Further, according to one embodiment of the present disclosure, the number of total beams available and the number of best beams may be indicated by beam reporting related information.

In addition, according to an embodiment of the present invention, the beam-reporting related information is information related to a beam reporting mechanism, and the terminal can acquire beam-reporting related information through an SIB (System Information Block) have.

Also, according to an embodiment of the present invention, the beam-reporting related signal may be either a beam reference signal or a CSI-RS (Channel State Information-Reference Signal).

The present disclosure can provide a method of reporting beam information.

The present disclosure can provide a method for transmitting best beam information among a plurality of beams.

The present specification can provide a reporting setting method for reducing the amount of information.

The effects obtainable in the present specification are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description will be.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

1 is a block diagram showing the configuration of a base station 105 and a terminal 110 in a wireless communication system 100. As shown in FIG.

Figure 2 is a diagram illustrating narrow beamforming associated with the invention.

3 is a diagram showing a Doppler spectrum when narrow beam forming is performed.

4 is a diagram showing an example of a synchronization signal service area of a base station.

5 is a diagram illustrating a method of performing communication between a terminal and a base station based on beamforming.

6 is a diagram illustrating a method of performing communication between a terminal and a base station based on beamforming.

7 is a diagram illustrating a method of performing beam reporting based on a differential offset.

8 is a diagram illustrating a method of performing beam reporting based on a relative difference offset.

Figure 9 is a diagram illustrating a method for performing beam reporting based on measurements for each beam.

10 is a diagram illustrating a method of performing beam reporting based on measurements for each beam.

11 is a diagram illustrating a method of performing beam reporting.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, those skilled in the art will appreciate that the present invention may be practiced without these specific details. For example, the following detailed description assumes that a mobile communication system is a 3GPP LTE and an LTE-A system. However, other than specific aspects of 3GPP LTE and LTE-A, Applicable.

In some instances, well-known structures and devices may be omitted or may be shown in block diagram form, centering on the core functionality of each structure and device, to avoid obscuring the concepts of the present invention. In the following description, the same components are denoted by the same reference numerals throughout the specification.

In the following description, it is assumed that the UE collectively refers to a mobile stationary device such as a UE (User Equipment), an MS (Mobile Station), and an AMS (Advanced Mobile Station). It is also assumed that the base station collectively refers to any node at a network end that communicates with a terminal such as a Node B, an eNode B, a base station, and an access point (AP).

In a mobile communication system, a user equipment can receive information through a downlink from a base station, and the terminal can also transmit information through an uplink. The information transmitted or received by the terminal includes data and various control information, and various physical channels exist depending on the type of information transmitted or received by the terminal.

The following techniques may be used in various wireless communication systems such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC- Communication systems, and the like. CDMA may be implemented in radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. The TDMA may be implemented with a radio technology such as Global System for Mobile communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be implemented in wireless technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and Evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS).

3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) is part of E-UMTS (Evolved UMTS) using E-UTRA, adopts OFDMA in downlink and SC-FDMA in uplink. LTE-A (Advanced) is an evolved version of 3GPP LTE.

In addition, the specific terms used in the following description are provided to aid understanding of the present invention, and the use of such specific terms may be changed into other forms without departing from the technical idea of the present invention.

The transmission from the base station to the terminal is referred to as downlink transmission and the transmission from the terminal to the base station is referred to as uplink transmission for wireless transmission between the base station and the terminal. A method for distinguishing radio resources between downlink transmission and uplink transmission is defined as a duplex, and when frequency bands are divided into a downlink transmission band and an uplink transmission band and bidirectional transmission and reception are performed, a frequency division duplex (Frequency Division Duplex) FDD). The technique proposed in the present invention shares a time and frequency resource with a time division duplex (TDD) in which time resources are divided into a downlink transmission time and an uplink transmission time in addition to the frequency division duplex, It is obvious that it can be operated in a bidirectional duplex (Full Duplex) which transmits and receives in both directions.

1 is a block diagram showing the configuration of a base station 105 and a terminal 110 in a wireless communication system 100. As shown in FIG.

Although one base station 105 and one terminal 110 are shown to simplify the wireless communication system 100, the wireless communication system 100 may include one or more base stations and / or one or more terminals .

1, a base station 105 includes a transmit (Tx) data processor 115, a symbol modulator 120, a transmitter 125, a transmit and receive antenna 130, a processor 180, a memory 185, a receiver 190, a symbol demodulator 195, and a receive data processor 197.

The terminal 110 includes a transmission (Tx) data processor 165, a symbol modulator 170, a transmitter 175, a transmission / reception antenna 135, a processor 155, a memory 160, a receiver 140, A demodulator 155, and a receive data processor 150. Although the transmission / reception antennas 130 and 135 are shown as one in the base station 105 and the terminal 110, respectively, the base station 105 and the terminal 110 have a plurality of transmission / reception antennas. Therefore, the base station 105 and the terminal 110 according to the present invention support a Multiple Input Multiple Output (MIMO) system. Also, the base station 105 according to the present invention can support both a Single User-MIMO (SU-MIMO) scheme and a Multi-User-MIMO (MU-MIMO) scheme.

On the downlink, the transmit data processor 115 receives traffic data, formats, codes, and interleaves and modulates (or symbol maps) the coded traffic data to generate modulation symbols Symbols "). A symbol modulator 120 receives and processes the data symbols and pilot symbols to provide a stream of symbols.

The symbol modulator 120 multiplexes the data and pilot symbols and transmits it to the transmitter 125. At this time, each transmission symbol may be a data symbol, a pilot symbol, or a signal value of zero. In each symbol period, the pilot symbols may be transmitted continuously. The pilot symbols may be frequency division multiplexed (FDM), orthogonal frequency division multiplexed (OFDM), time division multiplexed (TDM), or code division multiplexed (CDM) symbols.

Transmitter 125 receives the stream of symbols and converts it to one or more analog signals and further modulates (e.g., amplifies, filters, and frequency upconverts) the analog signals to transmit Lt; / RTI > Then, the transmission antenna 130 transmits the generated downlink signal to the terminal.

In the configuration of the terminal 110, the reception antenna 135 receives the downlink signal from the base station and provides the received signal to the receiver 140. The receiver 140 adjusts (e.g., filters, amplifies, and downconverts) the received signal and digitizes the conditioned signal to obtain samples. The symbol demodulator 145 demodulates the received pilot symbols and provides it to the processor 155 for channel estimation.

Symbol demodulator 145 also receives a frequency response estimate for the downlink from processor 155 and performs data demodulation on the received data symbols to obtain a data symbol estimate (which is estimates of the transmitted data symbols) And provides data symbol estimates to a receive (Rx) data processor 150. [ The receive data processor 150 demodulates (i.e., symbol demaps), deinterleaves, and decodes the data symbol estimates to recover the transmitted traffic data. The processing by symbol demodulator 145 and received data processor 150 is complementary to processing by symbol modulator 120 and transmit data processor 115 at base station 105, respectively.

On the uplink, the terminal 110 processes the traffic data and provides data symbols. The symbol modulator 170 may receive and multiplex data symbols, perform modulation, and provide a stream of symbols to the transmitter 175. A transmitter 175 receives and processes the stream of symbols to generate an uplink signal. The transmission antenna 135 transmits the generated uplink signal to the base station 105. The transmitter and the receiver in the terminal and the base station may be configured as one RF (Radio Frequency) unit.

In the base station 105, an uplink signal is received from a terminal 110 via a receive antenna 130, and a receiver 190 processes the received uplink signal to obtain samples. The symbol demodulator 195 then processes these samples to provide received pilot symbols and data symbol estimates for the uplink. The receive data processor 197 processes the data symbol estimates to recover the traffic data transmitted from the terminal 110.

The processors 155 and 180 of the terminal 110 and the base station 105 respectively instruct (for example, control, adjust, manage, etc.) the operation in the terminal 110 and the base station 105. Each of the processors 155 and 180 may be coupled with memory units 160 and 185 that store program codes and data. The memories 160 and 185 are connected to the processor 180 to store operating systems, applications, and general files.

The processors 155 and 180 may also be referred to as a controller, a microcontroller, a microprocessor, a microcomputer, or the like. Meanwhile, the processors 155 and 180 may be implemented by hardware or firmware, software, or a combination thereof.

(DSP), digital signal processing devices (DSPDs), programmable logic devices (PLDs), and the like may be used to implement embodiments of the present invention using hardware, , FPGAs (field programmable gate arrays), and the like may be provided in the processors 155 and 180.

Meanwhile, when implementing embodiments of the present invention using firmware or software, firmware or software may be configured to include modules, procedures, or functions that perform the functions or operations of the present invention. Firmware or software configured to be stored in the memory 155 may be contained within the processor 155 or 180 or may be stored in the memory 160 or 185 and be driven by the processor 155 or 180. [

Layers of a wireless interface protocol between a terminal and a base station and a wireless communication system (network) are divided into a first layer (L1), a second layer (L2) based on the lower three layers of an open system interconnection ), And a third layer (L3). The physical layer belongs to the first layer and provides an information transmission service through a physical channel. An RRC (Radio Resource Control) layer belongs to the third layer and provides control radio resources between the UE and the network. The UE and the base station can exchange RRC messages through the RRC layer with the wireless communication network.

The processor 155 of the terminal and the processor 180 of the base station in the present specification are not limited to the operation of processing signals and data except for the functions of the terminal 110 and the base station 105 to receive or transmit signals and the storage function, But for the sake of convenience, the processors 155 and 180 are not specifically referred to hereafter. It may be said that a series of operations such as data processing and the like are performed instead of the function of receiving or transmitting a signal even if the processors 155 and 180 are not specifically mentioned.

Fig. 2 is a diagram showing a narrow beamforming associated with the invention, and Fig. 3 is a diagram showing a Doppler spectrum when narrow beamforming is performed.

Since the very high frequency wireless communication system is located in a very high frequency band, it is possible to provide an antenna array having a small antenna and a plurality of antennas in a small space. This feature enables pin-point beamforming, pencil beamforming, narrow beamforming, or thin beamforming using tens to hundreds of antennas. This narrow beamforming implies that the received signal is only received at an angle rather than an isotropic direction.

FIG. 2 (a) shows a case where the Doppler spectrum appears in a U-shape according to a signal received in the backward direction, and FIG. 2 (b) shows a case where narrow beamforming using a plurality of antennas is performed.

Thus, narrow beamforming results in narrower Doppler spectra than U-shape due to reduced angular spread. As shown in FIG. 3, it can be seen that the Doppler spectrum in the case of performing narrow beamforming shows Doppler dispersion only in a certain band.

The wireless communication system using the above-described very high frequency band operates in the center frequency of several GHz to several tens GHz. This characteristic of the center frequency makes the influence of the CFO due to the Doppler effect generated due to the movement of the UE or the oscillator difference between the transmitter and the receiver more serious.

4 is a diagram showing an example of a synchronization signal service area of a base station.

The MS performs synchronization with the BS using a downlink (DL) synchronization signal transmitted from the BS. In this synchronization process, timing and frequency are synchronized between the base station and the terminal. In order for the terminals in a specific cell to receive and use the synchronization signal in the synchronization process, the base station constructs the beam width as wide as possible and transmits the synchronization signal.

On the other hand, in the case of a mmWave communication system using a high frequency band, a path loss is larger in a synchronous signal transmission than in a case of using a low frequency band. That is, in the case of a system using a high frequency band, a cell radius that can be supported in comparison with a conventional cellular system (for example, LTE / LTE-A) using a relatively low frequency band (for example, 6 GHz or less) Is greatly reduced.

As a method for solving the reduction of the cell radius, a synchronous signal transmission method using beam forming can be used. When beamforming is used, the cell radius is increased, but the beam width is reduced. Equation (1) below represents the change of the received signal SINR according to the beam width.

[Equation 1]

배 감소하는 경우, 수신 SINR이 배 향상됨을 나타낸다.Equation (1) shows that the beam width

Indicates that the received SINR is doubled.

As another method for solving the reduction of the cell radius in addition to the beam forming method, a method of repeatedly transmitting the same synchronizing signal can be considered. In this case, additional resource allocation is required on the time axis, but the cell radius can be increased without decreasing the beam width.

Meanwhile, the BS allocates resources to the UEs by scheduling frequency resources and time resources located in a specific zone. Hereinafter, this specific area is defined as a sector. In the sector shown in FIG. 4, A1, A2, A3 and A4 represent sectors with a radius of 0 to 200 m and widths of 0 to 15 ', 15 to 30', 30 to 45 'and 45 to 60', respectively. B1, B2, B3 and B4 represent sectors with a radius of 200 to 500 m and widths of 0 to 15 ', 15 to 30', 30 to 45 'and 45 to 60', respectively. A1, A2, A3, A4}, and sector 2 is defined as {A1, A2, A3, A4, B1, B2, B3, B4} based on the contents shown in FIG. In addition, when the synchronization signal service area of the current base station is sector 1, it is assumed that the base station requires additional power of 6 dB or more to transmit the synchronization signal to the sector 2 in order to serve the synchronization signal.

First, the base station can obtain an additional gain of 6 dB using the beamforming technique to service sector 2. This beamforming process can increase the service radius from A1 to B1. However, since the beam width is reduced through the beam forming, A2, A3, and A4 can not be simultaneously serviced. Therefore, when beamforming is performed, sync signals must be separately transmitted to the sectors A2 to B2, A3 to B3, and A4 to B4, respectively. In other words, the base station must transmit the sync signal four times over the beamforming in order to service sector 2.

On the other hand, when considering the repetitive transmission of the synchronous signal described above, the base station can transmit the synchronous signal to all of the sectors 2, but the synchronous signal must be repeatedly transmitted four times on the time axis. As a result, the resources required to service sector 2 are the same for both the beamforming scheme and the iterative transmission scheme.

However, in the case of the beamforming method, since the beam width is narrow, a terminal moving at a high speed or a terminal at the boundary of a sector is difficult to receive a synchronous signal stably. Alternatively, if the ID of the beam on which the terminal is located can be distinguished, the terminal can grasp its position through the synchronization signal. On the other hand, in the case of the iterative transmission scheme, it is very unlikely that the terminal will miss the synchronization signal due to its wide beam width. Instead, the terminal can not grasp its position.

5 is a diagram illustrating a method in which a base station and a terminal exchange signals based on beamforming.

As described above, in NR and mmWave systems, a base station (e.g., gNB) and a terminal may exchange signals based on beamforming. In this case, for example, the base station sets a beam in a specific direction, and the terminals located in the beam direction can communicate with the base station through a beam, which can be as shown in FIG.

At this time, the beam information needs to be reported in order for the base station and the terminal to set the beam. As an example, a beam reporting mechanism may be considered in NR and mmWave systems. According to the beam reporting mechanism, each of the terminals in the coverage from the base station can receive a reference signal (e.g. Beam RS, CSI-RS, ...). At this time, each of the terminals can report a plurality of best beams. The beam reporting mechanism may transmit a representative value (e.g., a median value or a highest value) so as to be a reference to reduce overhead. At this time, other reporting values can be reduced by reporting only differential offsets from representative values. However, errors may occur in accuracy for values that exceed the range defined by the offset or are not accurately represented by the offset. At this time, although the terminal can recognize the error, the base station may not recognize that the error value has been transmitted. In addition, since the terminal must report the measured value by the number of beams to be reported on the values within the range, the reporting of a plurality of beams must be performed, so that overhead may occur as many as the number of beams.

In the following, a description will be given of a method of reducing the overhead considering the correlation statistics between the beams in consideration of the characteristics of the beam in the mmWave system. In other words, a new beam management mechanism considering correlation statistic values reflecting the characteristics of NR and mmWave will be described.

6 is a view showing a beam reporting mechanism.

As described above, it may be necessary to reduce overhead when reporting beams in NR and mmWave systems. That is, a beam reporting mechanism may be needed to reduce the overhead in consideration of beam reporting, and to allow the base station to accurately grasp the beam reporting value transmitted from the terminal.

6, each of the UEs 610 and 620 receives a reference signal (e.g., beam RS, CSI-RS) characteristic of a beam measurement from a base station 630 at each antenna port So that the measurement can be performed. At this time, the UEs 610 and 620 can decode the measurement values received from the respective antenna ports. In addition, the UEs 610 and 620 can confirm the predetermined beam ID of the BS 630 and the UE and report M best beams among the N beams. At this time, the number of beams measured by the terminals is N and the number of best beams is M. However, N and M may be any number and may be set differently according to each situation.

For example, when M best beams are reported, the terminal may report information corresponding to M times the terminal beam reporting information. At this time, the reporting information may be expressed by the sum of the number of bits for representing the beam ID and the number of bits for representing the measured value per beam.

As an example, consideration may be given to the case of reporting the best beam M (= 6) based on the representative value and the differential offset for all N (= 32) beams in the NR. At this time, 4-bit wideband reporting (maximum value of 4 bits) may be configured as a representative value. At this time, M best beam reports can be performed using M-1 times (M-1) times 3-bit differential offsets of the 3-bit difference offset.

At this time, the feedback overhead necessary for best beam reporting can be calculated as shown in Equation (2).

&Quot; (2) "

More specifically, referring to FIG. 6, the base station 630 may form a total of N beams as described above. At this time, each of the UEs 610 and 620 can set M best beams as an optimal beam considering the positions of the UEs 610 and 620 among the N beams and other factors. At this time, each of the terminals 610 and 620 can perform reporting to the base station based on Equation (2) for the best beam.

However, considering the characteristics of the NR and the mmWave system, it may be necessary to reduce the overhead in Equation (2). That is, a beam reporting procedure may be required to reduce the number of bits to be reported at each of the terminals 610 and 620 and to increase the decoding accuracy at the base station 630, Describe.

7 is a diagram illustrating a method of reporting a best beam.

As described above, each of the terminals can report M best beams out of the total N beams transmitted from the base station to the base station. At this time, the M best beams may mean an optimal beam suitable for use by the terminal. The base station can select a beam to communicate with the terminal based on the best beam information received from the terminal, as described above.

Referring to FIG. 7, in the method of reporting the best beam, the first best beam based on the differential offsets is converted into the original measurement level (k-bits) like wideband reporting Can be reported. That is, for one of the best beams, reporting can be performed by allocating a large bit in consideration of all measurement information. At this time, the remaining beams (from the second beam to the Mth beam) can be expressed by only bits of information about the difference with respect to the first beam, and can be turned on. That is, the remaining M-1 beams are represented as difference information with respect to the first beam as " d-bits " as shown in FIG. 7 and can be reported. At this time, the offset value for the " d-bits " may be set differently according to the offset level. At this time, the larger the difference from the first beam, the more the number of bits can be increased. Therefore, the offset value for the " d-bits " is small in the second beam adjacent to the first beam, and the offset value for the " d-bits "

At this time, for example, a relative difference offset value may be used in place of the offset value for &quot; d-bits &quot; representing the difference from the first beam. At this time, when the relative difference offset value is "r" and the difference offset value is "d", it may be "r <d".

That is, when M best beams are reported, the overhead can be reduced by using the Ranking / Ordering characteristic, so that the relative difference offset value can be applied as shown in FIG.

At this time, referring to FIG. 8, the first best beam may be reported as original measurement level (k-bits) as in wideband reporting, as described above. The second best beam may then be reported as &quot; r-bits &quot; as the difference from the first best beam. Also, the third best beam may be reported as &quot; r-bits &quot; as the difference from the second best beam, not the difference from the first best beam. In the same manner, the M-th best beam can be reported as &quot; r-bits &quot; as a difference value from the (M-1) -th best beam. At this time, the relative offset value of &quot; r-bits &quot; may be set differently depending on the offset level. However, &quot; r-bits &quot; indicating information on the difference value of adjacent best beams may be smaller than &quot; d-bits &quot; That is, the number of bits to be reported by the terminal can be reduced.

)의 범위 내에 들어 오는지의 여부를 나타내며 기지국에 의해 알려지거나 단말에서 기정의될 수 있다.As another example, referring to FIG. 9, a method of reducing a feedback overhead using a correlation correlation characteristic may be provided. More specifically, the degree of correlation applied is determined by the degree to which neighboring beam IDs are displayed by correlation when selecting the M best beams (

) And may be known by the base station or may be defaulted at the terminal.

More specifically, the beam correlation can be distributed as shown in FIG. 9 based on the K-th beam index. At this time, the best beam located in a single crest can be regarded as an original measurement level as a reference value. The base station can recognize that nearby beams constitute the best beam and design beam reporting. At this time, the crest may mean a peak distribution. That is, this may mean that the measured value for a particular beam index is greater than the measured value for an adjacent beam index. For example, the measured values of the K-th beam index may be greater than the measured values corresponding to the (K-1) th and (K + 1) th beam indexes. In addition, the measured value becomes smaller as the beam index becomes smaller from the (K-1) th, and the measured value becomes larger as the beam index increases from the (K + 1) th. That is, the distribution of the peaks may be a crest.

Referring to FIG. 9, the K-th beam may be a reference beam. In this case, the measurement level may be a crest which is the highest in the K-th beam and gradually decreases in both directions, and the beam adjacent to the K-th beam may be the best beam, and beam reporting can be designed based on this.

Also, for example, referring to FIG. 10, the measurement level for each beam can be determined based on a double crest. At this time, referring to FIG. 10, it is possible to have a relatively high measurement level value at the K1-th and K2-th. That is, the shape may be a double crest distribution, and the terminal may design the beam reporting mechanism using relative offset values with the K1-th beam and the K2-th beam as reference values, respectively. This reduces the number of bits required for beam reporting.

Example

), 차이 오프셋 값(d) 및 상대적 차이 오프셋 값(r) 중 적어도 어느 하나 이상을 포함할 수 있다. The terminal and the base station may share the above-described information for the beam reporting mechanism. In addition, for example, the base station can transmit the above-described information to the terminal through SIB (System Information Block) information or an upper layer signal. For example, the information shared by the BS and the UE may include the total number of available beams N, the number of best beams M, the beam correlation level,

), A difference offset value (d), and a relative difference offset value (r).

At this time, the total number of beams N may be the total number of beams set on the terminal and the base station. Also, the best beam number M may be a beam having a preference as the number of beams that the terminal should report to the base station. That is, beams with high preferences can be sequentially reported to M base stations.

Next, the difference offset value may be a bit used for reporting the first best beam and the difference value for each best beam, as described above. For example, when d is 3 bits, it can be as shown in Table 1 below. At this time, the difference offset value can be set differently according to the offset level, which is as described above.

[Table 1]

In addition, the relative difference offset value may be a bit used for reporting as a difference value for an adjacent best beam as described above. In this case, as described above, the relative difference offset value may be smaller than the relative difference offset value (r <d). For example, when r is 2 bits, the relative difference offset value may be as shown in Table 2 below. The relative difference offset value may also be set differently depending on the offset level. However, the relative difference offset value may be smaller than the difference offset value, which is the difference value of the adjacent best beam, which is described above.

[Table 2]

)은 각각의 빔들의 상관 관계 정도에 기초하여 다르게 설정될 수 있다.Also, the correlation level (

May be set differently based on the degree of correlation of the respective beams.

Based on the above-described information, the terminal can perform a reporting configuration for reporting beam information, which can be as shown in Table 3 below. In one example, the reporting settings may be indicated by a 2-bit value. At this time, &quot; 00 &quot; has no correlation and can indicate the reporting setting using the existing differential offset value. &Quot; 01 &quot; has no correlation and can indicate a reporting setting using the Relative Differential Offset value described above. &Quot; 10 &quot; is a correlated beam that can indicate a reporting setting reporting each beam according to multiple Crest distributions. &Quot; 11 &quot; is a correlated beam, and can indicate a reporting setting reporting each beam according to a single crest distribution.

[Table 3]

Next, if the terminal and the base station share information on the beam reporting mechanism, the base station may transmit system information or a specific control signal to the terminal to trigger the beam reporting mechanism.

Next, when the terminal receives information on beam reporting from the base station, the terminal can trigger beam reporting and measure the signal received from the base station. At this time, the signal may be a reference signal as described above, and is not limited to the above-described embodiment. The measured value may be at least one of the RSRP, the RSRQ, and the CQI (Channel Quality Information) defined in the reporting mechanism. Further, for example, other values may be used as measurement values, and the present invention is not limited to the above-described embodiments. Next, the terminal can set the reporting mechanism based on the measured value. At this time, the established reporting mechanism can be indicated based on the above-described reporting setting.

As an example, an embodiment will be described based on the case of a 4-bit measurement report, 32 beams (N = 32), and 6 best beams (M = 6). However, the present invention is not limited to the above-mentioned number, and may be one embodiment for convenience of explanation.

)은 M개의 베스트 빔들이 넓은 범위를 가지면서 하나의 빔 근처에 형성되는 강한 상관 관계(Strong correlation)를 나타내거나, 좁은 범위에 속하면서 두 개 이상의 빔들 근처에 형성되는 약한 상관 관계(Weak correlation)를 나타낼 수 있다. 즉, 상관 관계 레벨은 빔의 분포에 기초한 정보일 수 있으며, 상술한 실시예로 한정되지 않는다.Also, the correlation level of the beams (

) Indicates a strong correlation formed by the M best beams having a wide range near one beam or a weak correlation formed between two or more beams while being in a narrow range . That is, the correlation level may be information based on the distribution of the beam, and is not limited to the above-described embodiment.

For reporting setting '00'

As described above, when the reporting setting is '00', there is no correlation, and only the difference offset value may be used.

Beam information can be reported on the basis of the above-described reporting setting in the case where a characteristic of M best beam values having a general independent measurement characteristic and a correlated beam characteristic showing a single crest or a double crest is excluded have. In addition, the difference offset values of the M best beams may not be represented by the relative difference offset value, the above-described reporting setting index may be set to 00, and reporting may be performed using the difference offset value at the base station.

For example, consider the case where the beam indexes of the six best beams are [10, 30, 12, 1, 5, 4] and the measurement levels are [15, 13, 7, 6, 5, 3]. At this time, since each good beam has no correlation property and a value larger than the relative difference offset value exists between the second beam and the third beam (13-7 = 6), it is difficult to use the relative difference offset value have.

Therefore, the reporting setting can be set to '00' as described above and reported as a difference offset value without correlation, which can be as shown in Table 4 above.

More specifically, based on the beam index, each beam ID may be assigned 5 bits. Also, as described above, the first best beam can be assigned 4 bits as the original measurement value. At this time, the second beam to the sixth beam can calculate the difference offset value. At this time, the offset level of each beam is 2, 8, 9, 10 and 12. Thus, based on Table 1 above, the offset offset values can be set to 1, 7, 7, 7, and 7. Thus, 5 * 3 bits can be allocated.

However, as described above, the following Table 4 is only one example, but the present invention is not limited thereto and the number may be changed.

[Table 4]

For reporting setting '01'

As described above, when the reporting setting is '01', there is no correlation and it may be the case of using the relative difference offset value.

When the difference values of the M best beams are always set to values smaller than 2 &lt; r &gt; except for the correlated beam characteristic showing the single crest or double crest, the UE can set the reporting setting to '01'. That is, if the difference values are less than 2 ^ r, the relative difference offset report can reduce the number of bits, which can be used. For example, if the indexes of the six best beams are [10, 30, 12, 1, 5, 4] and the measurement levels are [15, 12, 10, 7, 5, 3] Transmission using a difference offset can be performed.

More specifically, based on the beam index, each beam ID may be assigned 5 bits. Also, as described above, the first best beam can be assigned 4 bits as the original measurement value. At this time, the second beam to the sixth beam can calculate the relative difference offset value. At this time, the offset level of each beam is 3, 2, 3, 2 and 2. Thus, based on Table 2 above, the relative difference offset values can be set to 3, 2, 3, 2, and 2. Therefore, 5 * 2 bits can be allocated. However, as described above, the following Table 5 is only one example, but the present invention is not limited thereto, and the number may be changed.

[Table 5]

For the reporting setting '10'

As described above, when the reporting setting is '10', there is a correlation, and the correlated beams may have a plurality of crests. In one example, beam information reporting may be performed based on the above-described reporting settings when the M best beam measurement levels exhibit a weak correlation characteristic exhibiting a plurality of crests. For example, if the indexes of the best beams are [3, 12, 4, 11, 2, 13] and the measurement levels are [13, 12, 11, 11, 10, 10] It may be a case where the distribution is formed and is a double crest, and may be as shown in Table 6. At this time, the same method can be extended to a plurality of crests having a double crest or more.

More specifically, referring to Table 6, beam IDs can be reported as 3 and 12 as double crest beams. At this time, as the relative difference offset value of the crest beam, only the value of 13-12 = 1 can be reported.

Also, as an example, all beam IDs can be reported. At this time, the first best beam and the relative difference offset value can be reported and can be as shown in Table 6 below.

[Table 6]

For reporting setting '11'

As described above, when the reporting setting is '11', there is a correlation, and the correlated beams may have one crest.

For example, when the indexes of the six best beams are [7, 6, 8, 9, 5, 10] and the measurement levels are [13, 12, 11, 11, 10, 10] Lt; / RTI &gt;

More specifically, referring to Table 7, the beam ID can be reported as only 70 as a single crest beam.

Also, as an example, all beam IDs can be reported. At this time, the first best beam and the relative difference offset value can be reported and can be as shown in Table 7 below.

[Table 7]

Next, the base station can decode the reporting setting upon receiving the beam reporting value associated with the above-described reporting setting (2 bits) from the terminal. Accordingly, the BS can check the reporting settings transmitted by the MS. In one example, if the reporting setting is transmitted as '00', the base station may be aware of the difference offset reporting and may use the difference offset property from the beam ID and the best beam value to recover the information for each beam. For example, the base station may perform reporting information recovery for the beams as shown in Equation 3 below.

&Quot; (3) &quot;

In addition, for example, when the reporting setting is '01', the base station can recognize the relative difference offset reporting and perform the restoration using the beam ID and the relative difference offset value from each best beam value. In this case, for example, the base station may perform reporting information restoration for the beams as shown in Equation (4).

&Quot; (4) &quot;

In addition, for example, when the reporting setting '10' is transmitted, the base station may recognize a weak beam correlation with a plurality of crests (in the embodiment, double crests). In this case, for example, the selection of Alt1 or Alt2 in Table 6 may be preset by the BS or the MS.

For example, in the case of Alt 1 in Table 6, since a plurality of beam IDs having a plurality of crests and a plurality of reporting values are transmitted using relative difference offsets, they can be restored first. For example, in Table 6, the beam ID with the first crest is 3, and the measured value is 13. Also, the beam ID with the second crest is 12, and the measured value may be 12. The base station can recover information about the two beams as described above and additionally select two beams each near beam 3 and beam 12 as information about the best beam. That is, in the above embodiment having a double crest, the two groups may be [3,1,2] and [12,11,13]. Further, the present invention can be extended to a plurality of crests, and is not limited to the above-described embodiments.

Also, for example, in Alt 2 of Table 6 above, all relative difference offsets are reported, and all beams having double crest can be recovered. The beam IDs of [3, 12, 4, 11, 2, 13] and beam IDs of [13, 12, 11, 11, 10, 10] can be confirmed.

In another example, when the reporting setting is '11', the base station may be aware of the strong beam correlation with one crest. At this time, the base station can perform restoration by Alt1 or Alt2 based on Table 7 described above. For example, the selection of Alt 1 or Alt 2 may be preset by the base station or the terminal, and is not limited to the above-described embodiment.

In this case, for example, in case of Alt1, the beam ID transmitted in Table 7 may be 7. At this time, the measured value may be 13 days. In the case of Alt2, the transmitted beam IDs are [7, 6, 8, 9, 5, 10] and the measured values may be [13, 1, 1, 0, 0, 0].

When Alt1 is selected, since the base station transmits one reporting value with one representative beam ID 7 having a single crest, the base station needs to additionally select the best beam. The base station can additionally select five beams near beam 7. That is, a group having one crest can be [7, 4, 5, 6, 8, 9].

Also, in the case of Alt 2, the values of the beams having one crest are all reported as relative difference offsets using relative difference offset reporting, and thus can be restored. At this time, the beam IDs are [7, 6, 8, 9, 5, 10] and the measurement level values are the measurement levels [13, 12, 11, 11, 10, 10].

11 is a diagram illustrating a method in which a terminal reports beam information.

The terminal can acquire beam reporting related information from the base station (S1110). At this time, the terminal can share the beam reporting related information with the base station as described above with reference to FIG. 1 to FIG. At this time, the base station can provide beam-reporting related information to the terminal through the SIB or the upper layer signal. In one example, the beam reporting related information may be beam reporting mechanism related information, as described above.

Next, the terminal may trigger beam reporting (S1120). At this time, as described above with reference to FIGS. 1 to 10, the base station may enable the terminal to trigger beam reporting using system information or a control signal. The terminal may receive the system information or control signal to trigger beam reporting, as described above.

Next, the UE can receive the beam-related signal from the base station (S1130). At this time, as described above with reference to FIG. 1 to FIG. 10, the beam-related signal may be a reference signal. In one example, the reference signal may be Beam RS or CSI-RS. Other types of reference signals may also be used and are not limited to the embodiments described above.

The terminal can measure the beam reporting related signal. (S1140) At this time, as described above with reference to FIGS. 1 to 10, the UE can perform the measurement on each beam through the reference signal. As an example, measurements may be performed based on each beam index. The terminal can perform the reporting setting based on the measured signal, as described above.

Next, the terminal can report the beam information to the base station based on the measured signal (S1150). At this time, as described above with reference to FIGS. 1 to 10, the terminal can report the reporting setting to the base station together with the beam information have. At this time, the reporting setting may be composed of two bits and may be one of '00, 01, 10, and 11' described above. In one example, the terminal may perform reporting settings based on measurements for each beam. In this case, as described above, when the reporting setting is the first value ('00'), the beam information includes all of the measured value information of the first beam among the best beams, and the other of the best beams The information about the beams may include only the difference offset information based on the difference from the first beam. At this time, as described above, the first beam may be the representative beam or the first beam. Also, as an example, the first beam may be the beam with the highest measured value, and is not limited to the above-described embodiment. At this time, as described above, the original measured value is reported for the first beam, and only the difference offset value based on the difference from the first beam can be reported for the remaining beams, as described above.

When the reporting setting is the second value ('01'), the beam information includes all of the measured value information of the first beam of the best beam, and the information of the other beams other than the first beam of the best beam is Only the relative difference offset information based on the difference from the adjacent beam may be included. At this time, as described above, when the difference between the respective beams is small, the above-described reporting setting can be performed. That is, the second beam adjacent to the first beam, which is the first beam, may be reported as a difference offset value from the first beam. Also, the third beam can be reported as the difference offset value of the second beam. In the same manner, the Mth beam can be reported as the offset value of the difference from the (M-1) th beam, as described above.

Also, when the reporting setting is the third value ('10'), the available measurement values of all beams have a distribution profile based on a plurality of crests, and the beam information may include only information about the beams corresponding to the crest. At this time, the measured values of all available beams are distributed based on the beam index, and the beams corresponding to the crest may mean a beam having a measured value higher than the measured value of the beams corresponding to the adjacent beam index on both sides. In one example, the crest may be a section having a higher measurement value than the surrounding values. That is, it may mean a distribution pattern of a peak shape, which may mean the structure shown in FIG. 10 described above. That is, when the measured value of the beam corresponding to the Kth index is larger than the beam corresponding to the (K-1) th index and the beam corresponding to the (K + 1) th index, the beam corresponding to the crest corresponds to the Kth index Beam, which is described above. At this time, the terminal can report the beam information to the base station based on the Alt 1 scheme or the Alt 2 scheme described above. In addition, the base station can also recover the beam information based on the reporting settings, as described above.

Further, when the reporting setting is the fourth value ('11'), the available measurement values of all beams have a distribution based on one crest, and the beam information includes information about the beam having a large measurement value corresponding to the crest &Lt; / RTI &gt; At this time, the distribution having one crest may mean the distribution as shown in FIG. That is, the measurement values of the surrounding beams may be reduced based on the beam having the largest measurement value, and may be the reporting set in this case, as described above.

The above-described embodiments of the present invention can be implemented by various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

In the case of hardware implementation, the method according to embodiments of the present invention may be implemented in one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs) , FPGAs (Field Programmable Gate Arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, the method according to embodiments of the present invention may be implemented in the form of a module, a procedure or a function for performing the functions or operations described above. The software code can be stored in a memory unit and driven by the processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various well-known means.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The foregoing description of the preferred embodiments of the present invention has been presented for those skilled in the art to make and use the invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that Accordingly, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention.

In this specification, both the invention and the method invention are explained, and the description of both inventions can be supplemented as necessary.

The above description can be applied not only to 3GPP LTE and LTE-A systems, but also to various wireless communication systems including IEEE 802.16x and 802.11x systems.

Claims (20)

A method for a terminal to report beam information in a wireless communication system, The terminal acquiring beam-related information from a base station; Triggering beam reporting; Receiving a beam reporting related signal from the base station; Measuring the beam reporting related signal; And And reporting beam information to the base station based on the measured signal, The beam information includes information on a best beam among all available beams, Wherein the beam information is reported based on a Reporting Configuration. The method according to claim 1, The reporting configuration is comprised of two bits, The terminal reports the reporting configuration to the base station together with the beam information, And the base station restores the beam information based on the reporting setting. 3. The method of claim 2, If the reporting setting is the first value, the beam information includes all the measured value information of the first beam among the best beams, and information about the other beams other than the first beam among the best beams includes the first beam, And the difference offset information is based on a difference between the first offset information and the second offset information. 3. The method of claim 2, Wherein when the reporting setting is a second value, the beam information includes all the measured value information of the first beam among the best beams, and information on other beams excluding the first beam among the best beams includes Wherein only relative offset information based on the difference is included. 3. The method of claim 2, If the reporting setting is a third value, the measurements of the available total beams have a distribution based on a plurality of crests, Wherein the beam information includes only information about beams corresponding to the crest. 6. The method of claim 5, Wherein the measurements of the available total beams are distributed based on a beam index and wherein the beams corresponding to the crest refer to a beam having a measured value higher than the measured value of the beams corresponding to the adjacent beam index on both sides, Way. 3. The method of claim 2, If the reporting setting is a fourth value, the measurements of the available total beams have a distribution based on one crest, Wherein the beam information includes only information on a beam having a largest measured value corresponding to the crest. The method according to claim 1, Wherein the number of total available beams and the number of best beams are indicated by the beam reporting related information. The method according to claim 1, The beam-reporting-related information is information related to a beam-reporting mechanism, Wherein the terminal acquires the beam reporting related information through an SIB (System Information Block) or an upper layer signal. The method according to claim 1, Wherein the beam reporting related signal is one of a beam reference signal and a CSI-RS (Channel State Information-Reference Signal). A terminal for reporting beam information in a wireless communication system, A receiver for receiving a signal; A transmitter for transmitting a signal; And A processor for controlling the receiver and the transmitter, The processor comprising: Acquires beam-related information from the base station, Triggering beam reporting, Receiving a beam reporting related signal from the base station, Measuring the beam reporting related signal, and Reporting beam information to the base station based on the measured signal, The beam information includes information on a best beam among all available beams, Wherein the beam information is reported based on a reporting configuration. 12. The method of claim 11, The reporting configuration is comprised of two bits, The terminal reports the reporting configuration to the base station together with the beam information, And the base station restores the beam information based on the reporting setting. 13. The method of claim 12, If the reporting setting is the first value, the beam information includes all the measured value information of the first beam among the best beams, and information about the other beams other than the first beam among the best beams includes the first beam, And the difference offset information is based on the difference of the difference information. 13. The method of claim 12, Wherein when the reporting setting is a second value, the beam information includes all the measured value information of the first beam among the best beams, and information on other beams excluding the first beam among the best beams includes And only relative offset information based on the difference is included. 13. The method of claim 12, If the reporting setting is a third value, the measurements of the available total beams have a distribution based on a plurality of crests, Wherein the beam information includes only information on beams corresponding to the crest. 16. The method of claim 15, Wherein the measurements of the available total beams are distributed based on a beam index and the beams corresponding to the crest mean a beam having a measured value higher than the measured value of the beams corresponding to the adjacent beam index on both sides, . 13. The method of claim 12, And if the reporting setting is a fourth value, the measurements of the available total beams have a distribution based on one crest, Wherein the beam information includes only information on a beam having a largest measured value corresponding to the crest. 12. The method of claim 11, Wherein the number of total available beams and the number of best beams are indicated by the beam reporting related information. 12. The method of claim 11, The beam-reporting-related information is information related to a beam-reporting mechanism, Wherein the terminal obtains the beam reporting related information through an SIB (System Information Block) or an upper layer signal. 12. The method of claim 11, Wherein the beam reporting related signal is one of a beam reference signal and a CSI-RS (Channel State Information-Reference Signal).

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